Lying bastard

Just discovered my husband is a cheater. He came back today from a business trip and I’ve had some doubts so I snuck onto his laptop. I find saved emails from 2013 between him and his ex talking about meeting up for sex. We got married in 2012. I also discovered texts from someone in Germany where he’s just been talking about my how much they love each other! I am fuming and debating whether to go back upstairs and kill him (which I won’t but the temptation is strong!). I have messaged the German girl and emailed the ex as I want to understand the full scale of the infidelity. Any advice as to what to do next. As a Christian I know infidelity is grounds for divorce but I was so hopeful that would not be my story 😭😡😭😡😭